1. Field of Invention
This invention pertains to earth boring and more particularly to drill directing apparatus.
2. Description of Prior Art
It is known to drill a hole in the earth with a rotating bit. In such drilling, the bit may be loaded axially either by the weight of the drill stem to which the bit is connected or by application of fluid pressure to a piston or cylinder connected to the drill stem anywhere along its length between the bit and the mouth of the hole. The bit can be rotated by a motor connected to the drill stem anywhere between its inner end adjacent the bit and its other or outer end, which may be out of the hole at the earth's surface. It is known to guide the bit to cause the hole to be bored in any desired direction. For example, in U.S. Pat. Nos. 3,298,449 to Bachman et al., 3,326,305 to Garrett et al. and 3,460,639 to Garrett there is shown a bit deflection barrel around the drill stem and through which the drill stem moves axially as drilling proceeds, the drill stem being turned by an out of the hole motor. U.S. Pat. No. 2,637,527 to Andrews shows a deflection and force application barrel about a drill stem projectable into the hole as drilling proceeds and carrying an in-hole motor between the barrel and stem. It is also known to provide bit deflection means affixed to the bit or to the drill stem adjacent the bit, such deflection means moving axially in the hole as the bit proceeds. To take the reaction force of an in-hole bit loading device, an in-hole motor or a bit directing device, it is known to provide anchor means to engage the wall of the hole being drilled. This is shown for example in U.S. Pat. No. 556,718 to Semmer which also shows means for advancing an in-hole motor and bit loading device along the hole as it is drilled. Another example of such anchor means is the construction shown in the U.S. Pat. No. 2,946,578 to DeSmaele. See also U.S. Pat. to Kellner Nos. 3,088,532, 3,105,561, and to Kellner et al U.S. Pat. Nos. 3,180,436, 3,180,437, and to Roberts U.S. Pat. No. 3,225,844.